Sotheby’s raised the stakes in its negotiations with the art handlers union today when they locked out unionized employees from the auction house.

The 43 members of the Teamsters Local 814 were all handed letters as they clocked out on Friday telling them not to bother coming in to work today. Their previous contract with Sotheby’s expired early in July but negotiations, which stretched back to May, were still said to be progressing.

“It seems to me that they are putting the whole operation at risk,” said Local 814 President Jason Ide, in a statement. “Putting multi-million dollar works in the hands of a temporary crew is not a good idea.”

One sticking point in the negotiations would seem to be the hiring of additional union employees. The Local 814 press release notes that Christie’s met this condition in the union’s negotiations with that auction house in April.

Diana Phillips of Sotheby’s responded to this in her statement, saying, “One of the Union proposals has been the addition of 18 new union employees. This 42% increase would result in Sotheby’s employing significantly more property handlers than the total number of Christie’s union employees (also Local 814), despite the fact that Sotheby’s New York handled 54% fewer lots than Christie’s handled (based on publicly available information) in 2010.”

Mr. Ide told The Observer that Christie’s employs 51 union employees, but added that there’s been a misrepresentation of their hiring demands in the media.

“What we’re saying is, to the extent that they need 61 workers, those people should be union employees, and not temporary, untrained workers,” he said on the phone.